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Terrorism and National Emergencies

The UK MOD has used 5 alert states to warn of terrorist activity since August 2006. The five Terror Threat Levels replaced the outdated BIKINI state for nationwide emergencies. Information in this section explains how Britain alerts the general public about the likelihood of terrorism attacks, national hazards, and other emergency situations.

National Measures against Terror Attacks

The UK Government informs all citizens about any changes to the current threat level and its response to any terror attacks.

They enforce national measures against terrorism through various security services (e.g. JTAC, MI5).

As a member of the public, you should always remain vigilant and be alert to the dangers of terrorism.

You should always report any signs of suspicious activity to the police or the anti-terrorist hotline (further details below).

Important: Anyone can report suspicious activity to MI5 (e.g. if the information does not relate to an imminent threat).

What Does MI5 Stand For?

The initials ‘MI’ stand for military intelligence. Along with MI6, the two organisations form part of the Ministry of Defence (MOD).

They both acquired their official names from previous designations during the 1930s. But, their modern titles are the Security Service for MI5 and the Secret Intelligence Service for MI6.

UK Terror Threat Level Today: What Does it Mean?

Each terror threat level indicates the probability of a terrorist attack occurring in the United Kingdom. We define what the five threat levels mean in the list below.

MI5 and JTAC set the international terrorism threat level. Hence, the level of threat would be decided on a basis known as ‘categories of risk’. JTAC is the Joint Terrorism Analysis Centre in the UK.

International Terrorist Threats

The current threat from international terrorism to the England, Wales, Scotland, and Northern Ireland is severe (raised from substantial on the 15th of November 2021).

Northern Ireland-related Threats

The current threat to Northern Ireland from Northern Ireland-related terrorism is severe.

The current threat to Great Britain from Northern Ireland-related terrorism is moderate.

The 5 UK Terrorist Threat Levels

Each threat level shows a broad indication of the likelihood of suffering a terrorist attack. The United Kingdom uses five (5) levels of terrorism threat:

  • Critical: An attack is expected imminently
  • Severe: An attack is highly likely
  • Substantial: An attack is a strong possibility
  • Moderate: An attack is possible but not likely
  • Low: An attack is unlikely

UK threat levels can change at any time and they do not have an expiry date. Thus, changes occur as different information becomes available to the security agents.

Note: The UK raised its terror threat level to the highest level of ‘CRITICAL’ on September the 25th in 2017. JTAC has since changed the UK threat level from international terrorism back to ‘SEVERE’.

How Should the Public Respond?

In general, the public do not need to make any specific response to actual threat levels. Security practitioners use it as a tool for working across different security sectors. Furthermore, it helps police forces and the Critical National Infrastructure determine the best protective security response.

Vigilance and awareness is vital:

Everyone should be alert to the current national threat level. Sharing this insight with the public helps to keep people informed. It also explains the need for extra security measures (e.g. heightened airport security).

Information on International Terrorist Threat Levels

The MI5 website has further information about terrorism threat levels in the United Kingdom. The government website (GOV.UK) also has foreign travel advice for different territories and countries.


In simple terms, it combines military and political activities to prevent or combat terrorism. The main role of MI5 The Security Service is keeping our country safe. Their actions protect the United Kingdom against all threats to national security.

The Office for Security and Counter-Terrorism would coordinate a response by the government in any cases of a terrorist incident. Among other things, the police would also enforce counter-terrorism laws.

Public Safety Warnings

There are several ways of protecting a community, or an area, if there is a specific threat made to our national safety. As a rule, the government will issue a warning of such an incident to the public.

How to Report Suspected Terrorist Activity

You can remain anonymous if you want to report someone’s involvement in terrorism activities. You do not need to be certain the person is involved to:

Assessing National Emergencies

Emergency Preparations made by Government

Organisations take part in regular training exercises as part of preparing for natural emergencies. They include local councils and regional emergency services (e.g. fire, ambulance, and police forces).

The government also plans ahead to ensure essential services do not stop. They want to keep all vital services working in the event of an emergency. The key areas would be food, water, transport, as well as the health and financial service sectors.

The government also publishes guidance for local councils on the recovery process following an emergency. You can read the guide titled ‘Recovery: an emergency management guide‘. The booklet addresses 5 main challenges confronting local authorities.

National Risk Register (NRR) of Civil Emergencies

All kinds of natural hazards, and some man-made threats, can affect safety around the United Kingdom. The government carries out a continual assessment of these kinds of threats.

The National Risk Register of Civil Emergencies is a document that brings all such issues together. It explains the likelihood of a risk occurring from 2008 to the present day. It also covers the potential effects of an emergency if it was to happen.

Related Help Guides

Note: The short video explains why the Home Secretary said that the upgrading of the threat level from ‘substantial’ to ‘severe’ was a precautionary measure.

Terrorism Threat Levels and Emergencies in the United Kingdom